Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 30 Jan 2002 16:24:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 30 Jan 2002 16:24:15 -0500 Received: from femail43.sdc1.sfba.home.com ([24.254.60.37]:62944 "EHLO femail43.sdc1.sfba.home.com") by vger.kernel.org with ESMTP id ; Wed, 30 Jan 2002 16:23:45 -0500 Content-Type: text/plain; charset=US-ASCII From: Rob Landley To: root@chaos.analogic.com, Linux kernel Subject: Re: TCP/IP Speed Date: Wed, 30 Jan 2002 16:24:55 -0500 X-Mailer: KMail [version 1.3.1] In-Reply-To: In-Reply-To: MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <20020130212344.ZLSQ25963.femail43.sdc1.sfba.home.com@there> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 30 January 2002 11:07 am, Richard B. Johnson wrote: > When I ping two linux machines on a private link, I get 0.1 ms delay. > When I send large TCP/IP stream data between them, I get almost > 10 megabytes per second on a 100-base link. Wonderful. > > However, if I send 64 bytes from one machine and send it back, simple > TCP/IP strean connection, it takes 1 millisecond to get it back? There > seems to be some artifical delay somewhere. How do I turn this OFF? This is just a guess, but it sounds to me like a scheduling issue. When you're sending data from one network stack to another, how often the receiving program scoops data out of the incoming file descriptor isn't too much of a limiting factor, as long as you've got enough buffer space in the receiving network stack that the sender doesn't have to pause. But to bounce the data back, the program at the far end doing the receive and resend has be woken up and handed a time slice with which to receive, process, and return the packet. Have you tried ingo's O(1) scheduler? :) > Cheers, > Dick Johnson Rob - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/